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Please explain 'apple scaling' and the potential 'hit' on GPU

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ProgRocker

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Apr 24, 2018
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I'm looking to pick up a Mac Mini but I am reading about concerns with 'Apple Scaling' and the supposed hit on the GPU if you are not scaled properly. What exactly is this ? Can you use a 4k monitor without taxing the GPU ? Or does one need to just get a 5k ?
I was intending on getting a 4k 32" monitor, but after reading through many reviews I decided to wait until I better understand this issue.

Thanks........
 
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What Mini are you planning to get? The 2018 Mini with the Intel UHD 630 integrated graphics struggled to scale 4k screens to anything other than 1920x1080, this was discussed a lot here after it was introduced. I ended up getting a 32" 2560x1440 screen and running it at native resolution on my 2018 in order to avoid these issues.

I don't have an Apple Silicon Mini, but my understanding is that they don't have this issue.
 
There are four ways how you can use a monitor.

First, run at native resolution. This is usually done for 100-120ppi displays where about 110ppi is currently the "normal" size. This is the baseline.

Second you can run in retina mode where every logical/layout pixel uses 2x2 hardware pixels. This is usually done for 200-240ppi displays where 220ppi is, of course, the "normal" size and what Apple uses for external (non-laptop) retina displays. This doesn't incur any particular GPU overhead, however it is usually only used with high-PPI displays where running at native resolution would also be slightly more stressful for the GPU compared to simply having a display with fewer pixels.

Third there is running at any non-native resolution and letting the display scale to its native resolution. This is the traditional way of running a display at a different resolution and it doesn't incur any particular GPU overhead either. The quality of the scaling depends on the display.

Fourth is what Apple usually does nowadays for non-native resolutions, frequently used on displays whose PPI is the very common 140-170, i.e. too few for 1:2 retina (everything would be very large yielding a small desktop) but too much for 1:1 without any scaling (everything would be quite small). This incurs some overhead because if for example you choose "looks like 2560x1440" on a 27" with 3840x2160, aka "4K", to obtain a "normal" sized desktop then after rendering a 5120x2880 retina desktop the GPU scales that down to 4K before sending that to the display. Like the third option this mode also has slight blurring due to the non-integer scaling, however it is less noticeable due to usually being used with higher PPI displays.
 
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Basic75 gives a good rundown on how things work conceptually.

This is one of those things that is blown way out of proportion. My daily use machines are a 13" M1 MBP 16GB/1TB and an M1 mini 16GB/256GB.

I run the MBP at its default 1440x900 resolution, which is a scaled resolution by the way as the display is 2560x1600. Using Stats menus, I find that running the display at the scaled 1440x900 resolution typically uses a few percent (2%-5%) more GPU than running on the retina 1280x800 resolution during my daily productivity use.

I use the mini with an 32" LG 32UL500 4k display. I normally run it at native 3840x2160 resolution. That resolution allows me to work without a second display. When I give remote lectures, I'll drop down to a scaled 2560x1440 resolution. The result is pretty similar, the mini uses a few percent more GPU to render the the high dpi scaled resolution.

On the laptop, Apple does not let you choose from a full list of resolutions for the internal display, but will allow you to see all available resolutions for an external display. The external display will give options to choose between the high dpi scaled resolutions and low res options that just map the resolution to the display. I find the high dpi scaled resolutions to be well worth the GPU overhead when I want things to look larger on my display.

When the retina displays came out in 2012, it made no sense to me to use 4 pixels for every 1 pixel displayed because the GPUs on the entry level machines worked extremely hard to make it happen (I opted for the non-retina MBP back in 2013). With the M series chips 10+ years later, I really do not feel it is worth fussing over. If it's really a concern, then opt for a machine with a Pro, Max, or Ultra chip.
 
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I'm looking to pick up an M2/3 Pro or Max. I'll be using it primarily for music production.

I was hoping to get a 32" monitor though from what I've seen so far 32" monitors won't work... supposedly ??
I've come across this chart a few times, quite a few use this. It seems by the chart I have to go with a 34" 'curved' monitor which I don't really want or a smaller 27". This and the supposed scaling and GPU issues. Of which seems to be not as bad as I've been hearing. I'm coming from a PC btw, so this is all very new to me. Is this chart correct at all, or should I just disregard it, since I see Meson is using a 32" LG 32UL500 4k with no problems ?
Also I see from Basic75's post I need to pay attention to the PPI of a monitor as that plays an important role in how the display will perform. (There's a lot of conflicting info out there !)

Thanks for all the input and advice...

One additional question... In the context of music production, would I benefit from the 400GB/s of memory bandwidth on the Max or would the 200GB/s Pro suffice ?



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That chart basically says that Apple’s old standard of 110 pixels per inch or the newer 220 pixels per inch are the only acceptable resolutions for a Mac. I suppose that’s the case if you will only accept elements on the screen as being usable at looks like 2560x1440 on a 27” display. Personally I find that resolution to make things a little large for my taste.

Since Apple dropped antialiasing support at the OS level, even their 110 pixels per inch displays no longer look as nice as they used to. I much prefer the sharper image produced by 140 pixels per inch compared to 110 pixels per inch.

Your Mac will output to any display at any resolution it is capable of just as it has in the past. Some people find elements displayed at 3840x2160 at 32” too small for their taste. I find it works just fine for me, although I will admit that I wish someone made a 34”-35” 4k display to make things a smidge larger. Those that made the chart will have you believe that the only acceptable way to use a 4k 32” display is in looks like 1920x1080. That’s crazy! There is a fantastic resolution of 3008x1692 that looks great on a 32” display as well.

Yes, if you use a display with larger pixels, then things will not be as sharp as an Apple Retina display. If it really bothers you, you can push the display a little further from your eyes. I will say that I was first exposed to personal computers in the mid ‘80s as a kid and think we are extremely spoiled by the display panels we have available today. In the last two years I’ve used displays of 1680x1050 at 24” and 1920x1080 at 21” alongside my retina MBPs. While not ideal, the displays got the job done.

If only the best of the best will do, then either a 27” 5k or 32” 6k display will do. For those that are a little more pragmatic, I think you will find 32” @ 4k works very well.
 
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OP wrote:
"I was hoping to get a 32" monitor though from what I've seen so far 32" monitors won't work... supposedly ??"

What you've read from some others is nonsense, especially for your use case.
A 32" display will be fine.
You'll appreciate the extra "width" when working on music timelines.

For music production, I think that "non-4k" -- i.e., 2560x1440 (also called "1440p") will be "all you need" and look very good as well.
 
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